The present invention is related generally to the field of orthodontics.
One goal for orthodontic treatments is to improve a patient's cosmetic appearance and dental function. As discussed in U.S. Pat. No. 5,501,600, improving the appearance of one or more of a person's teeth has been undertaken previously by adding an aesthetically appearing porcelain veneer to a respective tooth or teeth.
The veneering process is historically complex, time consuming and expensive. By way of example, U.S. Pat. No. 4,473,353 describes one method for cosmetic restoration of anterior teeth. As discussed therein, a dental professional custom made a glazed porcelain labial veneer for a patient's tooth. Thereafter, he/she chemically and mechanically bonded the glazed porcelain labial veneer to the respective patient's tooth, to provide a healthful and long lasting cosmetic restoration of desired color, shape, and aesthetic appearance. In this method, conventional crown and bridge impression materials were used in taking an impression of the patient's teeth, and recordings were made pertaining to the patient's bite, shade and other pertinent data. The patient's impression was filled by pouring in die stone materials. A “Pindex” model was made, pinning all teeth to be veneered, as well as adjacent teeth. Each tooth die was undercut at the cervical extension, trimmed at the marginal areas of the regions to be veneered and hardened, so as to replicate the identical structure of the cosmetically defective tooth. A triangular shaped platinum foil was placed over the labial surface of the tooth die with the apex pointed downward and forming a tab portion which extends below the gingival margin. The base of the triangular shaped foil was folded over the incisal edge of the die and at least partially around the proximal surfaces, in such a manner as to form a snugly fitting, but hingedly removable at the top, foil sheath on the tooth die. For added retention, the foil was adhered to the previously made undercut. The platinum matrix was removed from the die using the tab portion formed by the foil apex and pulling the foil sheath hingedly off the incisal edge of the die, and the platinum matrix was then held over a Bunsen burner flame to decontaminate it. The platinum matrix was then reapplied to the die and burnished thereon. Porcelain was then applied to the labial surface of the platinum matrix using a brush, starting at the cervical undercut and working up to the incisal edge, and in so doing, the building up of the porcelain was undertaken thinly and uniformly. The platinum matrix (also called the foil matrix) with the porcelain was removed from the tooth die and placed on a tray, then in turn placed in a furnace for firing. The foil matrix and baked porcelain veneer thereon were then replaced on the tooth die. The marginal areas of the porcelain veneer were finished. Then the porcelain veneer was contoured into an aesthetic shape, and the labial anatomy was carved. The foil matrix and the porcelain veneer were removed from the tooth die for the last time, and the porcelain veneer was cleaned ultrasonically. Then the porcelain veneer was stained and glazed using conventional techniques to conform to the shade characteristics selected in respect to the patient's teeth. The room temperature foil matrix and porcelain veneer were placed in distilled water for one minute. Then using tweezers, the foil was gently removed from the porcelain veneer, leaving a thin clearance for the cement used to bond the veneer to the tooth. The intaglio, or inside surface, of the porcelain veneer was then etched, usually by air abrasion, to promote bonding thereof to the enamel tooth surface. Then the appropriate enamel surfaces of the patient's tooth were etched with an acid gel formulation, to create micropores in the tooth and thereby promote bonding. The intaglio surface of the porcelain veneer was then coated with a thin layer of light cured bonding agent, and a similar layer of the bonding agent was applied to the etched enamel bonding surface of the patient's tooth. Both of these layers of bonding agent were polymerized by light curing; and a coating of dental filler material was then applied to either the patient's tooth or the intaglio surface of the porcelain veneer. The porcelain veneer was placed onto the patient's tooth; excess filler material was trimmed away, and the filler material was polymerized by a second application of light; and the dentist finished the proximal and incisal margins to provide a smooth restoration surface.
U.S. Pat. No. 5,501,600 provides a method wherein a noble metal foil matrix, which conforms to the front tooth die of a patient, and a porcelain ceramic slurry, which will be applied to the metal matrix, are quickly and accurately obtained. The improved method of providing the porcelain ceramic slurry involves leaving a central area of the noble metal foil matrix uncovered during a first firing period to obtain the first layer of porcelain veneer. Leaving this initial area uncovered compensates for the shrinkage of the porcelain during the first firing period.
On a parallel note, removable dental positioning appliances with attachments are available. As discussed in U.S. Pat. No. 6,705,863, such removable dental positioning appliances usually comprise an elastic polymeric shell having a cavity for receiving at least some of a patient's teeth and are often preferred over conventional braces for tooth repositioning due to comfort, appearance and ease of use. These appliances function by applying force to specific surfaces of the teeth or dental features to cause directed movement. However, the type of movement and level of force applied is usually dependent on the surface characteristics and positions of the dental features. In many cases, the native tooth surface(s) and other dental features of a patient are inadequate to provide sufficient anchoring or to impart sufficient force on the teeth to be repositioned. To overcome these limitations, one or more attachment devices may be attached to preselected attachment points on the teeth or dental features to provide the appropriate physical leverage. Specific design and location of these attachment devices may provide newly achievable and/or more effective repositioning forces, anchoring ability and appliance retention. The use of attachment devices in combination with removable dental positioning appliances provides the patient with the benefits of removable appliances while retaining the ability to extrude, rotate, and otherwise manipulate teeth as with conventional braces. Like conventional braces, attachment devices may be bonded to the surface of the teeth in order to provide physical features which facilitate the application of controlled force. The attachment devices may have a very simple construction, in some instances being only a bump, bead, wedge, or other body or structure which can be fixedly attached to the surface of a tooth or other dental feature in order to transmit force generated by the dental positioning appliance to the dental feature and/or to anchor the positioning appliance to teeth in order to permit the appliance to apply forces elsewhere in the patient's teeth. These attachments may either be preformed and positioned into place using an aligner template as the positioning device, or they may be simultaneously created and bonded using a polymerizable material which is attached into the desired precise position using an attachment template. In either case it is the attachment template which facilitates bonding of the attachment at the desired position on the tooth.